Absorbent cores used to collect and contain bodily discharges are well known in the art. Absorbent cores are used in conjunction with disposable absorbent articles such as sanitary napkins, disposable diapers, and multi-component adult incontinence garments to collect and contain such discharges, which are typically liquid. Such articles may be disposable, reusable, integral, releasable and intended for wear by infants or adults.
The wearer of any articles utilizing an absorbent core, or the caretaker of a wearer, may become frustrated or irritated if the capacity of the absorbent core is exceeded, i.e., loading beyond that which can be absorbed by the core occurs and the core fails, i.e., bodily discharges are not contained by the core. Such discharges may run off the core and be transported outside the boundaries of the sanitary napkin, diaper, adult incontinence garment, or other absorbent article, and may soil the clothing or bedding of the wearer.
Typically, the total capacity of an absorbent core is not utilized prior to failure occurring and the core is theoretically able to collect and contain additional loadings of discharges when failure occurs. Failure often occurs because of lateral migration of deposited liquid bodily discharges. The discharges deposited on the absorbent core may laterally migrate to either longitudinal side margin of the absorbent core, particularly if such discharges are not deposited coincident with (or even near) the longitudinal centerline of the absorbent core. Upon failure, further loading of discharges does not penetrate the core and become absorbed thereby, but rather becomes run-off and breaches the longitudinal side margins of the article which utilizes such a core.
Several attempts have been made in the art to guard the longitudinal side margins of absorbent articles from lateral run-off of deposited liquids. For example, some sanitary napkins have been provided with liquid impervious partitions which overlay the core. Such liquid impervious partitions may be interposed between the absorbent core and the topsheet or may overlay the topsheet. In either embodiment, however, the partitions reduce the effective target area of the absorbent core. This occurs due to liquids deposited on the partitions usually do not penetrate to the core. Instead, the liquids deposited onto the partitions run, along the outside of the partitions, through and past the longitudinal side margins of the absorbent core, and breaches the absorbent article associated with the absorbent core.
Another attempt in the art to notify the wearer or caretaker that an absorbent garment is nearing its capacity and ready to be changed is a wetness indicator. A wetness indicator, such as the type disclosed in U.S. Pat. No. 4,231,370 issued Nov. 4, 1980 to Mroz et al., typically reacts to the pH of discharged bodily fluids by changing color. However, such wetness indicators are typically applied to the inwardly oriented face of a transparent backsheet and do not react to notify the wearer or caretaker of loading, unless the core is loaded substantially throughout its thickness. Thus, discharged body fluids which are not absorbed into the thickness of the core will fail to register with a wetness indicator on or adjacent the face of the absorbent core opposed to the wearer. Also, such wetness indicators impose opacity limitations on the selection of the backsheet material.
Typically, the absorbent core of such articles is rectangularly shaped, for ease of manufacturing. However, there is frequently a wearer preference for an absorbent core which is narrower at the center than at the ends, to comfortably accommodate the legs, and obviate or minimize occurrences of bunching or wadding of the core. Such wearer preference is more frequently encountered when the absorbent core is utilized in conjunction with a sanitary napkin.
Accordingly, it is an object of this invention to provide an absorbent core and a means for indicating the incipiency of a frequent mode of failure, i.e. lateral run-off from the absorbent core, is about to occur. It is also an object of this invention to provide a means for visually indicating when the capacity of an absorbent core is about to be exceeded. It is further an object of this invention to visually indicate incipient failure of the core without reducing its target area. Finally, it is an object of this invention to provide visually discernible indicia which enhance the apparent shape of the absorbent core to the wearer.